Atlantic Meridional Transect cruise AMT30 (DY157) micro-molar nutrient measurements from CTD bottle samples collected in 2023.

This dataset consists of measurements of micromolar nutrient concentrations made on samples collected during the Atlantic Meridional Transect programme cruise 30 (AMT30 DY157) on the RRS Discovery, between 20th February and 30th March 2023. The cruise track, between Port Stanley, Falkland Islands, and Southampton, UK, passed through both north and south Atlantic Oceans and through the central gyre of the South Atlantic. This dataset contributes to the AMT time-series of core oceanographic measurements along a south-north transect of the Atlantic Ocean. Samples were collected on a daily basis at all sampled CTDs (total of 56) and depths (according to GO-SHIP protocols), with samples taken to a depth maximum of 500 m at most CTDs. A CTD rosette with 24 x 20L OTE (Ocean Test Equipment) bottles was used for sampling. Samples were analysed within 2-3 hours of collection for nitrate+nitrite, nitrite, phosphate and silicate using a 4-channel SEAL Analytical AAIII segmented flow, colorimetric, auto-analyser. The analytical methods used were Brewer and Riley (1965) for nitrate, Grasshoff (1976) for nitrite, and Kirkwood (1989) for phosphate and silicate. Established, proven analytical protocols were used and clean sampling and handling techniques were employed, all following International GO-SHIP nutrient protocols (Becker et al., 2020). Certified Nutrient reference materials from KANSO Ltd, Japan (Batch BU), were used during the cruise to ensure good quality control and reliable analytical results.

本数据集包含2023年2月20日至3月30日期间，搭载于英国皇家研究舰“RRS Discovery”号的大西洋经向断面计划（Atlantic Meridional Transect，AMT）第30次科考航次（AMT30 DY157）所采集样本的微摩尔级营养盐浓度测定数据。本次航次的航行路线从福克兰群岛斯坦利港出发，终点为英国南安普敦，途经北大西洋与南大西洋，并穿过南大西洋中部环流区。本数据集为沿大西洋南北断面采集的核心海洋观测AMT时间序列提供数据支撑。所有56个CTD（温盐深仪，Conductivity-Temperature-Depth）站位均按每日频次采集样本，采样深度遵循GO-SHIP（Global Ocean Ship-based Hydrographic Investigations Program）规程；绝大多数站位的最大采样深度为500米。本次采样使用搭载24个20升OTE（Ocean Test Equipment，海洋测试设备）采水器的CTD采水架。样本采集后2至3小时内，采用4通道SEAL Analytical AAIII分段流动比色自动分析仪，对硝酸根+亚硝酸根、亚硝酸根、磷酸盐及硅酸盐进行分析。本次分析采用的方法分别为：硝酸根与亚硝酸根联合测定采用Brewer与Riley（1965）法，亚硝酸根测定采用Grasshoff（1976）法，磷酸盐与硅酸盐测定采用Kirkwood（1989）法。所有操作均遵循国际GO-SHIP营养盐分析规程（Becker等，2020），采用经验证的成熟分析流程与规范的采样处理技术。本次航次期间使用了日本KANSO有限公司生产的认证营养盐标准物质（批次BU），以保障分析质量控制与结果的可靠性。